1. Field of the Invention
The present invention relates to a recording device for recording/erasing a visible image on/from a recording medium with which recording or erasing of the visible image can be repeatedly performed by opacifying or transparentizing the medium, a thermal energy.
2. Description of the Related Art
A permanent image is recorded on a conventional hard copy by forming an image on a recording medium such as a sheet of paper externally, with a developer, such as ink or toner, or a visible image may be formed on a recording layer which is provided on a base material such as thermosensitive recording paper.
However, recently, in accordance with setting-up of various types of networks, and the widespread of facsimile and copy machines, the amount of recording medium in use has been drastically increased, causing social problems such as the destruction of nature including destruction of forests, and refuse disposal. In consideration of the problems, there rises a great demand for recyclable recording paper and reduction of the consumption amount of recording medium. Consequently, great attention is presently being paid to recyclable recording media upon which recording/erasing can be repeatedly performed.
As a recyclable recording medium there is proposed a recording medium which can reversibly switch between transparent and opaque states in accordance with its temperature.
When the temperature of the recording medium in a transparent state at room temperature T1 is heated from T1 to temperature zone T4-T5 which is higher than the T1, the medium becomes opaque; That the medium changes its state from the transparent to the opaque state, and maintains the opaque state even after the temperature lowers back to room temperature T1. Further, when the temperature of the recording medium which is opaque state at room temperature is raised from T1 to transparent temperature zone T2-T3 (T1&lt;T2-T3&lt;T4-T5), and then lowered back to room temperature T1, the medium changes from the opaque state to the transparent state where it remains. Thus, switching between the transparent and opaque states can be repeatedly carried out.
A report on deterioration of resolution when the above-described method for recording via such a recording medium was repeatedly performed with a thermal head, is repeated.
Further, there is proposed a display revising device for displaying/erasing data on a display using a thermo-reversible recording medium. The revising device includes thermal erasing means for thermally erasing data on the display, and thermal recording means for thermally recording data. A specific example thereof is a device for recording/erasing data on/from a data recording card having a thermo-reversible recording layer by use of a heat roller (thermal erasing means) and a thermal head (thermal recording means).
There is also proposed a recording material in which a leuco-compound which exhibits a reversible variation in color tone by means of heat energy is employed as a color development source.
However, regarding thermal erasing means such as the heat roller mentioned above, it is necessary to maintain the temperature of the heat roller at the optimum value. Since the heat roller having a large heat capacitance is used to maintain a constant temperature, the size of the device is inevitably large.
Since the heat capacitance is large, there is a long delay from when the device is turned-on until when the device is ready to start an operation. Further, the temperature of the device must be maintained at constant even when recording/erasing operations are not carried out, resulting in waste of electrical power.
In a recording device having separate conveying means for each of the thermal recording means and the thermal erasing means, it is likely that the motion speeds of both conveying means differ from each other. When the device is made to have a structure in which a recording medium is interposed between both recording and erasing means so as to make the size of the device small, a slip (trace) is caused on the recording medium due to the difference between both means in motion speed. The slip (trace) causes problems including displacement of a recorded image, deterioration of an image caused by opacification of one section to be erased, due to concentration of heat to the section, and wear-off of a recording medium in a short time by heat.